President Donald Trump urged Republicans on Tuesday to challenge a new Pennsylvania congressional map that could give Democrats a boost in November's midterm elections.

On Monday, the state's Supreme Court released redrawn boundaries that will take effect for this year's critical congressional elections. In January, the Democrat-majority court ruled Pennsylvania's previous GOP-crafted map showed partisan interests and violated the state's constitution.

The new boundaries for Pennsylvania's 18 districts give Democrats a better chance of picking up several congressional seats in the swing state as they try to win a House majority in November. Democratic gains of seats, or control of the House, could deal a blow to Trump's policy agenda starting next year.

On Tuesday, Trump urged the GOP to "challenge the new 'pushed' Congressional Map, all the way to the Supreme Court, if necessary." He told Republicans: "Don't let the Dems take elections away from you so that they can raise taxes & waste money!"

Republicans are expected to file a challenge to the district lines in federal court as early as this week. In a statement, Republican Party of Pennsylvania Chairman Val DiGiorgio called the new map "a partisan gerrymandering and power grab by Democrat Party operatives hiding behind robes."

"One can only conclude the Democrats have done with their maps the very thing they sought to redress with their lawsuit – packing and cracking voters for partisan gain," he contended.

Electoral effects

The GOP won 13 of 18 House seats in three straight elections under the previous map, even though the state's voters are more evenly split between the two major parties. Pennsylvania was considered one of the strongest examples of partisan gerrymandering in the country.

The new state map "is composed of congressional districts which follow the traditional redistricting criteria of compactness, contiguity, equality of population, and respect for the integrity of political subdivisions," a court order said.

If the new map had been in place during the 2016 election, Trump would have carried two fewer congressional districts in Pennsylvania than he actually did, according to the Philadelphia Inquirer.

To win the House majority in November, Democrats need to gain 24 seats. They have targeted Republicans in swing districts won by Democrat Hillary Clinton in 2016, as well as GOP lawmakers in some areas carried by Trump.

The new boundaries will not apply to a competitive March special election in Pennsylvania's 18th District. GOP Rep. Tim Murphy resigned from the traditionally safe Republican seat last year.